i bought a 56 chevy 4 dr sedan i would like to know how much it is worth

i bought it from a lady that bought it brand new 52 years ago it has 85,000 miles on it it still has the original sticker on the window, but what is throwing me off is it has a tire on the back of it and i cant seem to find another one like that. i am new at this, actually this is my first purchase of an old car.please tell me it is worth something.

It sounds like it has a continental kit on the back!
The price fluctuates depending on, of course, any rust issues, options ( v8 vs. 6 cyl., ps, pb, etc. ). It is not worth the same as a similar condition Bel Air. Post some pics. We can get a better idea from that. Mark